Why Radon Mitigation Matters
Whether you’re a contractor safeguarding your clients’ homes or a homeowner protecting your family, radon mitigation is essential. As the second leading cause of lung cancer in the U.S., radon poses a serious health risk, with 1 in 15 homes having elevated levels. Americover provides durable, compliant vapor barriers to help contractors deliver reliable results and homeowners create healthier living spaces.
What is a Radon Mitigation System?
A radon mitigation system is any system or steps designed to reduce radon concentrations in the indoor air of a building. The EPA recommends that you take action to reduce your home’s indoor radon levels if your radon test result is 148 Becquerels per meter cubed (148 Bq/㎥) or 4 picocuries per liter (4 pCi/L) or higher.
Radon mitigation with the help of crawl space vapor barriers is a crucial aspect of regulatory compliance and safety. It can reduce the flow of soil gas using a vapor barrier with a “soil gas retardant” membrane.
Where is the most potential for elevated indoor radon levels?
This map can be found on: The EPA Map of Radon Zones | US EPA
Zone 1 (red zones) Highest potential; average indoor radon levels may be greater than 4 pCi/L (picocuries per liter)
Zone 2 (orange zones) Moderate potential; average indoor radon levels may be between 2 and 4 pCi/L
Zone 3 (yellow zones) Low potential; average indoor radon levels may be less than 2 pCi/L
How Does a Radon Mitigation System Work?
A radon mitigation system is designed to reduce radon levels in buildings by preventing the gas from accumulating indoors. Radon is a naturally occurring, radioactive gas that forms from the breakdown of uranium in soil, rock, and water. It enters homes through cracks in floors and walls, construction joints, or gaps around pipes. Below is an explanation of how a typical radon mitigation system works:
1. Soil Gas Collection
The first step in radon mitigation is to intercept radon gas before it enters the building:
- Sub-Slab Depressurization: To collect radon gas, a pipe is inserted into a space beneath the foundation, typically in a gravel layer or a perforated pipe network.
- Crawl Space Systems: A durable vapor barrier (or soil gas retarder) is installed over the soil to prevent radon from seeping into the living space. The barrier is sealed, and radon gas is collected from beneath it.
2. Ventilation System
The collected radon gas is safely vented outside:
- Vent Pipe: A vertical PVC pipe carries radon gas from beneath the foundation to above the roofline.
- Fan Assistance: An inline fan is installed to create suction, actively drawing radon out of the soil and venting it into the atmosphere. This process is called an active radon mitigation system.
3. Pressure Differences
Mitigation systems also reduce the pressure difference between the soil and the indoor space to minimize radon entry:
- The fan lowers air pressure below the foundation, creating a barrier that prevents radon gas from being pulled into the building due to natural pressure imbalances.
4. Sealing Cracks and Openings
While the system collects and vents radon, sealing cracks and openings in the foundation is an important supplementary measure. This ensures radon gas is funneled into the system rather than escaping into the living space.
5. Continuous Monitoring
A radon mitigation system should include a manometer or monitoring device to indicate the system is functioning properly. Regular radon testing is recommended to ensure radon levels remain below the EPA’s action level of 4 picocuries per liter (pCi/L).
Standards for Vapor Barriers in Mitigation Systems
In the United States, the American National Standards Institute (ANSI) and the American Association of Radon Scientists and Technologists (AARST) have established guidelines for radon mitigation systems, including using soil gas retarders, commonly called vapor barriers. These standards align closely with ASTM specifications to ensure performance and durability in radon-resistant construction.
One key standard, ANSI/AARST CC-1000-2018, specifies that vapor barriers used for radon mitigation must be pliable plastic sheeting with low permeability, designed to create a durable barrier between soil gas and enclosed building spaces. Materials like 10-mil or thicker reinforced polyethylene sheeting are often recommended. Additionally, vapor barriers must comply with ASTM E1745, which outlines requirements for plastic sheeting used in contact with soil or granular fill under concrete slabs. This includes:
- Low Permeability: A permeance of 0.1 perms or less (per ASTM E96) to limit radon gas and moisture transmission.
- Material Durability: Resistance to punctures, tears, and other construction-related damage.
- Classification: Class A materials, offering the highest durability, are recommended for radon mitigation projects.
Furthermore, ANSI/AARST RRNC-2020 emphasizes the importance of installing continuous vapor barriers, such as reinforced polyethylene sheeting, over soil gas collection systems or exposed earthen floors to effectively retard radon flow.
These standards, recognized by the U.S. Environmental Protection Agency (EPA), serve as a benchmark for ensuring radon-resistant construction practices. For more details, visit standards.aarst.org.
Certified Radon & Gas Mitigation Vapor Barriers
While ASTM E1745 primarily measures moisture permeability, materials that meet this standard are often considered suitable for radon applications due to their low permeability characteristics. However, if you’re looking for a premium solution explicitly certified for radon or gas mitigation, explore our top-performing products to meet your needs.
VaporBlock Plus™
Color
Size
Vapor Barrier Retarder
Color
Size
Tuff-Scrim™
Color
Size
Thickness
Specification
Thickness
Specification
Thickness
Specification
Top Selling Crawl Space Vapor Barriers
Americover is a trusted provider of American-made crawl space vapor barriers. Our products are made with high-quality virgin resin, ensuring durability and reliability. Unlike general-use plastic sheeting or Visqueen alternatives, our vapor barriers are specifically designed to resist off-gassing and premature degradation, providing long-lasting protection for your crawl space.
Pro Crawl Anti-Mold Vapor Barrier with MPT™️️
Color
White/Pink
Size
Pro Crawl Barrier™ 10 Mil Class 1 Vapor Barrier
Color
Size
20 Mil Dura-Skrim® Reinforced Plastic Sheeting
Color
Size
Thickness
Thickness
Thickness
Specification
Specification
Specification
Perm Rating
Perm Rating
Perm Rating
20 Mil Dura-Skrim® Reinforced Plastic Sheeting
Color
Size
12 Mil Dura-Skrim® Reinforced Plastic Sheeting
Color
Size
8 Mil Dura-Skrim® Reinforced Plastic Sheeting
Color
Size
Thickness
Thickness
Thickness
Specification
Specification
Specification
Perm Rating
Perm Rating
Perm Rating
International Test Standards Definitions
ASTM E96
ASTM E1745
ASTM F1249
ASTM D1434
Standard Test Methods for Water Vapor Transmission of Materials
“1.1 These test methods cover the determination of water vapor transmission (WVT) of materials through which the passage of water vapor may be of importance, such as paper, plastic films, other sheet materials, fiberboards, gypsum and plaster products, wood products, and plastics. ”
Link to ASTM E96
Standard Specification for Plastic Water Vapor Retarders Used in Contact with Soil or Granular Fill under Concrete Slabs
“This specification covers flexible, preformed sheet membrane materials to be used as vapor retarders in contact with soil or granular fill under concrete slabs.”
Standard Test Method for Water Vapor Transmission Rate Through Plastic Film and Sheeting Using a Modulated Infrared Sensor
“1.1 This test method covers a procedure for determining the rate of water vapor transmission through flexible barrier materials. The method is applicable to sheets and films up to 3 mm (0.1 in.) in thickness, consisting of single or multilayer synthetic or natural polymers and foils, including coated materials. It provides for the determination of (1) water vapor transmission rate (WVTR), (2) the permeance of the film to water vapor, and (3) for homogeneous materials, water vapor permeability coefficient.”
Standard Test Method for Determining Gas Permeability Characteristics of Plastic Film and Sheeting
“1.1 This test method utilizes a manometric method to determine the steady-state rate of transmission of a gas through plastics in the form of film, sheeting, laminates, and plastic-coated papers or fabrics. This test method provides for the determination of (1) gas transmission rate (GTR), (2) permeance, and, in the case of homogeneous materials, (3) permeability.”
ASTM D3873
ASTM G21
Test Method K124/02/95
Standard Test Method for Valency State of the Arsenic Component of Ammoniacal Copper Arsenate Solutions
“1.1 This test method is intended for testing batches of concentrated ammoniacal copper zinc arsenate (ACZA) solution, prepared by air-oxidation of trivalent arsenic. The test method provides a means of confirming that oxidation has been completed and that at least 99.5 % of the arsenic has been oxidized. The sample for testing should contain 100 ± 20 mg of potential As2 O5. A200-mL aliquot of a concentrate containing 8 to 12 % of preservative oxides is suitable.”
Link to ASTM D3873
Standard Practice for Determining Resistance of Synthetic Polymeric Materials to Fungi
“1.1 This practice covers determination of the effect of fungi on the properties of synthetic polymeric materials in the form of molded and fabricated articles, tubes, rods, sheets, and film materials. Changes in optical, mechanical, and electrical properties may be determined by the applicable ASTM methods.”
Standard Test Method for Water Vapor Transmission Rate Through Plastic Film and Sheeting Using a Modulated Infrared Sensor
“Test Method K124/02/95 is a European test standard developed by the Swedish Radiation Safety Authority (SSI) to measure the radon diffusion coefficient of building materials. This test determines how well a material can resist the passage of radon gas, which is critical for evaluating its effectiveness in radon mitigation systems.”
Trust Americover with your next crawl space vapor barrier purchase.
American-Made Vapor Barriers
Better Quality Results
Multi-layered, extrusion laminated & reinforced
Tear resistance for increased service life
Low permeance barrier (<0.03)
Class A permeance rating
Prevents of structural damage
Reduces pest infestations
Increases energy efficiency
Improves indoor air quality
How Do You Measure a Crawl Space for a Vapor Barrier?
To measure your crawl space for a vapor barrier you will need to take the following measurements:
• Length of crawl space
• Width of crawl space
• Height of the foundation walls, or as high up on the walls you are going to encapsulate
• Perimeter Length of the entire space (length + width) multiplied by 2
Since most crawl spaces are less than 4′ tall, using a 4′ or 6′-wide vapor barrier for the walls will keep the seams to a minimum.
Watch a tutorial about how to calculate the square footage of your crawlspace.
Which Mil Thickness is Right for Your Crawl Space Vapor Barrier?
The video to the left will help you understand which mil thickness is best for your crawl space. A 6 mil vapor barrier is the minimum thickness recommended for encapsulation, but we advise you to take into consideration the following conditions:
- Ground conditions
- Traffic frequency
- Radon presence
- Geographical location
Compare Vapor Barrier Product Options
Shop By Mil Thickness
Crawl Space Vapor Barrier Accessories
Vapor Tape
White Vapor Tape is a heavy duty, weather resistant tape often used to seam large panels of poly sheeting together for vapor retarders, crawl space liners, covers and other liner applications. This tape is sold in individual rolls of 4″ x 180′.
2-Sided Butyl Tape
Double sided butyl tape is an insoluble tape with an aggressive adhesive that bonds plastic sheeting to porous surfaces such as concrete in crawl spaces. The waterproof bond adheres best when the application surface is clean and dry.
Ratchet Fasteners
Christmas Tree Ratchet Fasteners are made of heavy duty nylon with a 1/4″ diameter, flat white head and conical tip. Ratchet fasteners are used to attach vapor barriers to the foundation wall & are available in packs of 100 pieces or 500 pieces.
EnkaVent
Enkavent is a geocomposite ventilation mat designed to help manage soil gases, including radon, by creating an air channel beneath building foundations. Its 0.75-inch-thick nylon matrix allows radon gas to move freely and be directed to venting systems, preventing it from accumulating indoors. It is typically installed below concrete slabs or crawl space liners, working alongside vapor barriers to provide an effective, passive, or active radon control solution.
Why Americover?
Get your product when and where you need it
Contractors fight enough delays between weather, equipment failures, labor shortages, and subcontractor delays. The last thing you need is essential products like vapor barriers failing to arrive on time.
For over 25 years, Americover has built a proud reputation by getting contractors what they need when they need it. From the point that you first consider our products, we offer you a long-lasting and comprehensive partnership.
Contractors and Builders Talk About Americover
When you partner with Americover, you benefit from our industry and product application knowledge.
But don’t take it from us. Take it from those in the building industry who have relied on our quality and reliability over the years.
Check out our online selection of specialty plastic building solutions. Contractors and distributors are eligible for special pricing and volume-based discounts on select products, call us at 760-237-8786. Our online inventory is just our retail selection, which means we can often source items you may not see here.
Crawl Space Resources
Americover’s Product Catalog
Browse our full inventory of vapor barrier and crawl space encapsulation liner products.
Conversion Calculators for Easy Measurements
We’re doing the math for you! Get started with our easy-to-use conversion calculators.
Crawl Space Product Line Card
Compare the technical specifications of each product to find the perfect crawl space vapor barrier for every job.
Crawl Space Product Accessories Line Card
Find the accessories are essential for crawl space encapsulation.
Radon Mitigation Solutions Line Card
Learn more about the vapor barrier products used in Radon Mitigation applications.
How to Install a Crawl Space Vapor Barrier
Americover’s crawl space vapor barriers and liners are manufactured in America with virgin resins and uv inhibitors, if installed properly it should last up to 20 years or more. Purchasing at your local hardware store may be less expensive and more convenient, but it is likely to be compounded mostly of recycled resins containing a lot of debris and contamination which can cause off gassing, as well as shorten the lifespan of the liner causing it to degrade much faster, and requiring it to be replaced much sooner than anticipated. For more information on Virgin poly vs Regrind visit our Blog.
1. Cut the Vapor Barrier to size. The vapor barrier liner comes folded and rolled on a core. It is easier to cut and size the liner material before you take it into the crawlspace. After the material is cut to size roll it up (white side on the inside) so when you unroll it in your crawlspace it stays clean.
a. To cut the Floor Pieces, measure and cut a piece of vapor barrier liner material wide enough to cover the floor from the wall to the 1st line of piers or support then proceed to measure and cut the remaining floor pieces.
i. IMPORTANT: Don’t forget to measure enough material to seal an overlap of 6-12 inches on the wall pieces and pieces beside it.
b. For the Wall, keep the seams to a minimum by using a 4 ft or 6ft wide vapor barrier, since most crawlspaces are less than 4′ tall.
2. Start with the walls. To attach the liner, apply the 2 sided butyl tape 4 inches – 6 inches down from the top of the wall or sill plate. (This is to leave a space for pest inspection). *Do not remove the release liner on the exposed side of the tape until you are ready to attach the liner. (It may be easier to first apply the butyl tape to the vapor barrier, and remove the release liner as you are applying it to the wall.) otherwise, remove the release paper from the butyl tape in about 4 feet – 6 feet increments.
3. Fasten the Liner with some type of permanent fastener every 24 – 30 inches. The fasteners should go through both the material and the butyl tape. This can be accomplished by one of the following methods:
a. Use a Hilti
b. Use a Ramset Powder Fastener
c. Drill a 5/16″ hole and press in our Christmas Tree Ratchet Fasteners
4. Installing Vapor Barrier on the Floor. Starting at the piers or support posts, cut and notch the vapor barrier on both sides of the support about 6-12 inches above the ground. Wrap the vapor barrier to fit tightly around the support, and use the 4 inch white Vapor Tape to seal the material.
5. Smooth the liner out from the supports to the wall and tape the seams with the 4″ White Vapor Tape.
a. Overlap the Seams 6 inches to 12 inches.
b. You may remove your footwear or use disposable shoe covers to keep the vapor barrier liner clean.
Backup Under Slab Vapor Barrier 9 April, 2014 Americover's under slab vapor barrier passes ASTM E1745 class A. This is a high performance material designed to stop moisture migration and control gas. 
Best Vapor Barriers 7 April, 2022 Vapor barriers are essential for containing moisture build-up and preventing damage to foundations and walls. This plastic sheeting is most commonly installed in areas prone to excessive moisture such as crawl spaces, basements, and under concrete. With so many options on the market, it can be difficult to know which… 
Best Vapor Barriers for Walls 14 March, 2024 In-wall vapor barriers play an important role in protecting homes against potential issues. But many of these benefits vary depending on the location of your property. Vapor barriers control the flow of moisture and air within the home and can be a fantastic option if you live in the suitable…
For Contractors and Distributors, we offer special pricing, volume discounts, short lead times and a dedicated account manager who will work with you to get exactly what you need. If you would like to speak with a representative, contact us at 760-237-8786.